This invention relates to the mixing of chemicals with liquids, and more particularly to dispensers for dissolving a solid chemical into a flowing liquid stream.
It is sometimes necessary to feed a small amount of chemical, such as a polyphosphate or sodium silicate, into a water supply to control corrosion, iron staining or scaling. This can be accomplished by diverting a part of the water through a dispenser that holds a supply of the chemical in solid form and then returning the diverted water and the chemical it has dissolved back to the main body of flowing stream of water. Serious problems have arisen because the dispensers used previously did not provide consistant chemical flow at a given liquid flow rate or at varying liquid flow rates. Also, such dispensers often discharged a surge of chemicals when the liquid flow was begun after having been shut down for several hours.